This invention relates generally to electric circuit breakers of the electromagnetic type and more particularly to circuit breakers with arrangements for indicating the electrically tripped "open" condition of the circuit breaker.
Circuit breakers with arrangements for indicating the electrically tripped "open" condition of the circuit breaker contacts are shown in U.S. Pat. Nos. 3,742,402 and 3,742,403, both assigned to the Heinemann Electric Company. Further, a circuit breaker of the electromagnetic type is shown, for example, in Camp U.S. Pat. No. 3,329,913, also assigned to the Heinemann Electric Company.
Such electromagnetic circuit breakers typically comprise a movable contact, mounted on a movable arm, and a stationary contact. An operating handle is coupled to the movable arm via a linkage mechanism, part of the linkage mechanism comprising a collapsible toggle assembly. The movable and stationary contacts are operated between the contacts open and the contacts "closed" positions by pivoting the operating handle. The circuit breaker further comprises an electromagnetic device which in response to predetermined electrical conditions, collapses the toggle assembly, to thereby electrically trip open the contacts.
The circuit breakers shown in U.S. Pat. Nos. 3,742,402 and 3,742,403 incude auxiliary switches which are moved from an initial position, upon electrical tripping of the linkage mechanism, to a second position, upon electrical tripping of the circuit breaker, to indicate (in the second position) the tripped open condition of the circuit breaker contacts. The auxiliary switch remains in this second position until the circuit breaker contacts are manually reclosed at which time the auxiliary switch is reset to its initial position. Thus, to disconnect (or remove) the electrical signal provided by the auxiliary switch, it is necessary to move the circuit breaker handle to its contacts "on" position. However, if a fault current persists in the line, when it is attempted to manually reclose the contacts, it may not be desirable to do so.